Hi guys, I've been studying the datasheet of the PIC18F87K22 regarding its ENVREG pin which is the voltage regulator pin. I have some confusion here and I hope you guys can clarify for me. I'm migrating a PIC18F8722 design to this PIC18F87K22. The PIC18F8722 is using 5V voltage right? If I want to use 5V to power up the PIC18F87K22 too, does that means I have to enable the ENVREG pin?

Thanks.
Another thing, there's regions on my PCB where 5V will be used and there are regions where 3.6V will be use. The input power supply I'm using is 24V. So, I'm planning to use LM2596-5.0 to produce the 5V and LM2596-ADJ to produce the 3.6V.
The question is, should I use 5V(from LM2596-5.0) or 24V(from power supply) on the input voltage for LM2596-ADJ to produce 3.6V? Which voltage do you guys think is better?